From a91fb3de0d15b5ea9ad0156aff201b234ea10b42 Mon Sep 17 00:00:00 2001
From: Nero <41307858+nero@users.noreply.github.com>
Date: Fri, 19 Feb 2021 08:57:21 +0000
Subject: [PATCH] Implement common char i/o functions

---
 com/@rdos.asm   |  35 ++++++------
 kernel/char.asm | 144 ++++++++++++++++++++++++++++++++++++++++++------
 2 files changed, 144 insertions(+), 35 deletions(-)

diff --git a/com/@rdos.asm b/com/@rdos.asm
index 34a62e2..7bc6e42 100644
--- a/com/@rdos.asm
+++ b/com/@rdos.asm
@@ -3,36 +3,35 @@
 	jmp init
 
 %defstr V VERSION
-banner:	db "RDOS ", V, 0x0A, 0x0D, 0, 0x1A
+banner:	db "RDOS KERNEL ", V, 0x0A, 0x0D, '$', 0x1A
 
 %include "kernel/far.asm"
+%include "kernel/char.asm"
 %include "inc/bpb.asm"
 %include "kernel/drive.asm"
 
 section .text
 
 init:	call rstseg
-	mov si, banner
-.l01:	lodsb
-	test al, al
-	jz .l02
-	mov ah, 0x0e
-	xor bx, bx
-	int 0x10
-	jmp .l01
-.l02:
 	call dinit
 
-	mov dl, 0
-	call logdrv
+	mov dx, banner
+	call puts
 
-	xor ax, ax
-	xor dx, dx
-	call maprd
+	mov byte [testbuf], 5
+	mov dx, testbuf
+	call gets
 
-	inc word [dskbuf+0x80]
-	call dirty
-	call flush
+	mov ax, [testbuf]
+	mov cx, [testbuf+2]
+	mov dx, [testbuf+4]
+	mov bx, [testbuf+6]
+
+	int 3
 
 hlt:	hlt
 	jmp hlt
+
+section .bss
+
+testbuf	resb 130
diff --git a/kernel/char.asm b/kernel/char.asm
index 700cda3..cf6ea6e 100644
--- a/kernel/char.asm
+++ b/kernel/char.asm
@@ -1,30 +1,140 @@
+section .data
+
+conbx	dw 7
+
 section .text
 
-getc:	call conin
-	test al, al
-	jz getc
-	ret
-
-putc:	; flag checking here
-conout:	mov al, dl
+	; raw console output
+	; IN	dl	character
+conout	mov al, dl
 	mov ah, 0x0e
-	xor bx, bx
+	mov bx, [conbx]
 	int 0x10
 	ret
 
-conio:	cmp dl, 0xFF
-	jne conout
-conin:	call const
+	; check if character has characters ready
+	; OUT	al	0xFF if data, 0 if none
+const	mov ah, 1
+	int 0x16
+	jz .emp
+	mov ax, 0xFF
+	ret
+.emp	mov al, 0
+	ret
+
+	; read character from console
+	; OUT	al	character or zero
+conin	call const
 	test al, al
 	jz .ret
 	mov al, 0
 	int 0x16
-.ret:	ret
+.ret	ret
 
-const:	mov ah, 1
-	int 0x16
-	jz .emp
-.rdy:	mov ax, 0xFF
+	; dummy: write to auxillary dev
+auxout	ret
+
+	; dummy: read from auxillary dev
+auxin	mov al, 0x1A
 	ret
-.emp:	mov al, 0
+
+	; dummy: lister out
+lstout	ret
+
+	; character input with echo
+	; OUT	al	character
+getc	call const
+	test al, al
+	jz getc
+	call conin
+	push ax
+	mov dl, al
+	call putc
+	pop ax
+	ret
+
+	; character input without echo
+readc	call const
+	test al, al
+	jz readc
+	jmp conin
+
+	; character output
+	; IN	dl	character
+putc	jmp conout
+
+	; direct console I/O
+	; IN	dl	character to output or 0xFF if input
+	; OUT	al	character to read
+dcon	cmp dl, 0xFF
+	je conin
+	jmp conout
+
+	; output character string
+	; IN	ds:dx	far ptr to string, '$'-terminated
+puts	push si
+	mov si, dx
+.loop	lodsb
+	cmp al, '$'
+	je .ret
+	mov dl, al
+	call putc
+	jmp .loop
+.ret	pop si
+	ret
+
+	; send a beep ctl to console
+beep	mov dl, 0x07
+	jmp conout
+
+	; buffered input
+	; IN	ds:dx	far ptr to buffer
+gets	mov si, dx
+	mov cx, [si]
+	mov ch, 0
+	; ch = actual number of chars
+	; cl = maximum number of chars
+.loop	call readc
+	cmp al, 0x0D
+	je .cr
+	cmp al, 0x08
+	je .bs
+	cmp al, 0x20
+	jc .loop
+	; check if there is space in the buffer
+	; emit a beep if not
+	mov dl, cl
+	dec dl
+	cmp ch, dl
+	jc .append
+	call beep
+	jmp .loop
+	; append to buffer
+.append	mov bh, 0
+	mov bl, ch
+	mov [si+2+bx], al
+	inc ch
+	mov dl, al
+	call putc
+	jmp .loop
+	; handle backspace
+.bs:	test ch, ch
+	jz .loop
+	mov dl, 0x08
+	call putc
+	mov dl, 0x20
+	call putc
+	mov dl, 0x08
+	call putc
+	dec ch
+	jmp .loop
+	; handle carriage return
+.cr	mov bx, 0
+	mov bl, ch
+	mov [si+2+bx], al
+	mov [si], cx
+	mov dl, 0x0A
+	call putc
+	mov dl, 0x0D
+	call putc
 	ret